This invention relates, in general, to interface adapters for computer peripheral devices, and, more specifically, to an interface adapter that converts the type of data interface utilized by a computer peripheral device to communicate with a computer.
Computers utilize computer peripheral devices, such as optical disk drives, magnetic tape drives, and compact disc read only memory (CDROM) drives, for secondary data storage and retrieval, as well as for other myriad uses. In order for computers to utilize such devices, the computer and the associated device must be capable of communicating in some fashion to allow the device to perform the functions requested of it by the computer. This communication is normally embodied in a standardized set of hardware components, signal protocols and software commands, which are collectively termed a xe2x80x9ccomputer peripheral data interfacexe2x80x9d. The physical portion of the interface typically consists of an multi-conductor cable with connectors on each end, and the appropriate circuitry on the computer and peripheral device to allow electrical signals to be transmitted and received over the cable. Several such data interfaces commonly employed today include, for example, the Small Computer System Interface (SCSI), the AT Attachment (ATA) interface, and the Universal Serial Bus (USB). Even within each type of computer peripheral interface, several different variations of those interfaces can exist, as can be witnessed by the assorted configurations of SCSI available, such as Fast SCSI, Fast Wide SCSI, Ultra SCSI, and the like.
Some computer peripheral devices require the use of one or more interfaces aside from the main data interface. For example, CDROM drives generally employ an audio interface, which often is connected via a cable to a sound card resident in a computer. Additionally, power is usually supplied to the drive by way of yet another cable.
Some differences in data interfaces relate primarily to the mechanical configuration of the connectors and cables involved with the interface. For example, RS-232C-based serial interfaces exist in a multitude of mechanical configurations, and conversion between the various types is normally accomplished by way of a simple adapter, such as a pin-to-socket type converter. Another example of a related type of adapter for peripheral devices may be found in U.S. Pat. Nos. 4,936,785 and 5,040,993.
However, with the advent of the various types of computer peripheral data interfaces now available, each with a different hardware signal protocol and software command set, such as those mentioned above, providing more than one interface on a peripheral device has become more problematic due to the substantially different hardware and firmware requirements for each data interface.
The computer peripheral data interface chosen by a user for a particular combination of computer and peripheral device depends on a few important factors. For instance, the physical placement of the device in relation to the computer system is an important consumer consideration. A computer peripheral device that is manufactured specifically to reside within the main computer case is usually termed an xe2x80x9cinternalxe2x80x9d device. Conversely, a device that is designed to reside outside of the computer in a separate housing is known as an xe2x80x9cexternalxe2x80x9d device. Generally speaking, an external device will be more expensive than a comparable internal unit, due at least partially to the additional requirement for an external case and power supply. Obviously, an external device may occupy more desk space than a similar internal device, as well. However, in exchange for these disadvantages, an external device allows more portability than a related internal model, as the user would likely need to open the computer case to extract an internal device for use with another computer system.
Once the decision of using an external or internal device has been made, the number of possible computer peripheral data interfaces that may be used is typically narrowed. For example, the ATA interface is used almost exclusively in internal configurations, USB is primarily employed as an external interface, and SCSI, depending on the hardware utilized, can be used in either an internal or external configuration.
The xe2x80x9cinternal versus externalxe2x80x9d choice also affects the physical configuration of other interfaces employed by the device. More specifically, the audio connector of a CDROM drive tends to be different for an external drive unit when compared to its internal counterpart. Also, the connection for power delivery from a computer to an internal drive unit is usually quite different from that of a normal external power supply utilized by external, portable devices.
Parameters other than system configuration, such as price and performance, also have an effect on the choice of computer peripheral data interface. As an example, SCSI configurations generally cost more and provide higher performance than ATA systems. Such considerations further influence the data interface choice of most users.
Therefore, with such data interface options available to the consumer, it is often in the best interests of the peripheral device manufacturers to provide as many of the more popular data interfaces for each type of device they sell as is economically feasible. For example, a CDROM drive manufacturer may want to sell both an ATA and a SCSI version of their drive in order to broaden the appeal of their product.
Unfortunately, producing multiple versions of a peripheral device, one for each type of computer peripheral data interface, is usually rather expensive, both for the manufacturer and the consumer. Generally, manufacturers employ either of two methods to address the issue. One method involves making a single version of the drive capable of supporting one standard data interface, and then adding an xe2x80x9cinterface converterxe2x80x9d, consisting of a relatively expensive printed circuit board with a set of connectors that mate with the interface connectors of the device, and another set of connectors for interfaces employed by the computer. The interface converter, which usually resides outside of the chassis of the peripheral device, may be housed in a separate case, or in an expanded case along with the device. The expense of the interface converter is due primarily to the amount of circuitry that would be necessary to translate the signal protocols and software commands of the interface on the computer side of the converter to those associated with the xe2x80x9cnative,xe2x80x9d or preexisting, interface of the device. One interface converter is needed for each type of data interface to be supported other than the native interface.
The second method commonly employed by device manufacturers when providing more than one interface for a particular product is to actually make separate main printed circuit boards for the device, one to provide the hardware and embedded software (or xe2x80x9cfirmwarexe2x80x9d) for each interface to be supported. Although this approach eliminates the problem of requiring the user to buy a separate converter, other problems arise, specifically with respect to manufacturing, testing and inventory control. Instead of manufacturing and testing one device, which would require just one manufacturing and testing line, a separate line would be required for each supported interface, just as if the various data interface versions of the drive were each completely separate products. Inventory control also becomes problematic, as the quantity in inventory of the various components of the device that differentiate the multiple data interface versions should, to a certain degree, reflect the number of each type of device to be sold in the future. Such quantities have been difficult historically to predict.
Accordingly, there exists a need for a simple and cost-effective means to connect a computer peripheral device to a computer by way of more than one computer peripheral data interface.
In a possible embodiment, the invention provides a simple interface adapter that allows the conversion of the data interface hardware of a computer peripheral device. Such an adapter permits the manufacturing of a single type of peripheral device, thereby simplifying the manufacturing, testing, and inventory control of the device. Furthermore, the adapter does not require the space or expense of typical interface converters.
The adapter, as a possible embodiment of the invention, provides a means to physically connect a computer to a computer peripheral device that contains the circuitry and associated firmware necessary to communicate via all data interfaces that the manufacturer of the device wishes to provide. This capability has become more prevalent in recent years, as advances in integrated circuit technology allow more functionality to occupy less space on a printed circuit board. Due to these advances, manufacturers of integrated circuits that implement a portion of the data interface are now able to implement more than one such data interface within a single IC package, with the interfaces usually being multiplexed on the same signal lines.
In addition to the actual physical connector conversions required, the adapter also provides a means for indicating to the peripheral device which of the supported interfaces is to be used when communicating with the computer. In an example embodiment, the indication of the interface to be utilized is accomplished by a simple electrical conductor connecting two interface conductors of the device. The device may then, using any appropriate hardware and firmware necessary, reconfigure the internal circuitry of the device to use the indicated data interface.
In some cases, the computer peripheral device provides a connector for only one of the supported data interfaces. A possible embodiment to address this situation involves an adapter that contains a connector that mates with the data interface connector on the device. The adapter would then also include a connector that allows connection with the cable for the data interface being used by the computer.
In another possible embodiment, the peripheral device would instead utilize a general-purpose connector not intended to connect to any specific peripheral interface. Alternately, the device could just provide a set of conductive pads on an edge of the main printed circuit board of the device. In either case, an example embodiment of the adapter would have an appropriate connector to interface with the general-purpose connector or conductive pads of the device, along with a connector for connection to the peripheral interface cable to be used.
In each case, other interfaces separate from the peripheral device data interface may also need to be converted from one physical configuration provided by the drive to another expected by the computer or other unit. For example, the audio and power interfaces of CDROM drives, mentioned above, tend to be different for external drives, as compared to their internal counterparts. Any physical conversion necessary for such interfaces from the device to the computer or another external unit are also accomplished by the invention in an example embodiment.
In another representative embodiment, the computer peripheral device contains connectors for all of the peripheral data interfaces supported by the device, but any other interfaces used by the device may still need to be converted to an alternate physical configuration, depending on, for example, whether the device is to be configured for internal or external operation. A possible embodiment of the invention in this case would be an adapter with audio and power connectors that mate with the corresponding connectors on the device, as well as a set of audio and power connectors that are compatible with those provided by cables connected to the computer.
In all of the preceding embodiments, the necessary connections between the connectors that mate with the device and those that mate with the various interfaces may be accomplished with simple wiring. Optionally, the connections may be made in some embodiments with traces on a small printed circuit board.
In yet another representative embodiment, the present invention may also be implemented as a method of providing the same type of connections afforded by the use of the adapter embodiments discussed above by allowing the electrical connection of the interface conductors located on the peripheral device to the cable connectors of the data interface employed by the associated computer, and supplying an indication to the device of the identity of the computer peripheral data interface to be used.
Other attributes and advantages of the invention will become apparent from the following detailed description and accompanying drawings, illustrating by way of example the principles of the invention.